JBigI: GMP 6.2.0 for linux 64 bit (ticket #1869)

Add support for zen and zen2
Enable more fallbacks for zen and zen2
Adds Zen and Zen2 binaries, stripped
Built with gcc 9.3.0
Other binaries will be added if testing shows improvement
Fix hangs in mbuild-all.sh build script
Add silvermont and goldmont to build script, untested, support TBD
GMP is GPLv2
More info: http://zzz.i2p/topics/2955

core/c/jbigi/download_gmp.sh

@@ -1,10 +1,10 @@
 #!/bin/sh
 #
-#       This script downloads gmp-6.1.2.tar.bz2 to this directory
+#       This script downloads gmp-6.x.x.tar.bz2 to this directory
 #       (if a different version, change the GMP_VER= line below)
 #
 
-export GMP_VER=6.1.2
+export GMP_VER=6.2.0
 export GMP_TARVER=${GMP_VER}
 export GMP_DIR="gmp-$GMP_VER"
 export GMP_TAR="gmp-$GMP_TARVER.tar.bz2"

core/c/jbigi/mbuild-all.sh

@@ -50,7 +50,7 @@ TRANSLATE_NAME_armv7a="armv7"
 # Note! these build on 32bit as 32bit when operating as 32bit...
 # starting with k10 added for 6.0.0
 # As of GMP 6.0.0, libgmp 3,
-X86_64_PLATFORMS="skylake coreisbr coreihwl coreibwl bobcat jaguar bulldozer piledriver steamroller excavator atom athlon64 core2 corei nano pentium4 k10 x86_64"
+X86_64_PLATFORMS="zen2 zen silvermont goldmont skylake coreisbr coreihwl coreibwl bobcat jaguar bulldozer piledriver steamroller excavator atom athlon64 core2 corei nano pentium4 k10 x86_64"
 TRANSLATE_NAME_x86_64="none" # Rename x86_64 to none_64, since that is what NativeBigInteger refers to it as
 
 # Note! these are 32bit _ONLY_ (after the 64 bit ones)
@@ -84,7 +84,7 @@ if [ ! -f "$JAVA_HOME/include/jni.h" ]; then
     exit 1
 fi
 
-if ! command m4 > /dev/null; then
+if [ ! $(which m4) ]; then
     printf "\aWARNING: \`m4\` not found. Install m4 " >&2
     printf "and re-run this script.\n\n\n\a" >&2
     exit 1
@@ -140,7 +140,7 @@ else
   exit 1
 fi
 
-if ! command ${CC} > /dev/null; then
+if [ ! $(which ${CC}) ]; then
   echo "The compiler you've selected \"$CC\" does not appear to exist"
   exit 1
 fi